Long-range diastereoseIectivity in Ugi reactions of 2-substituted dihydrobenzoxazepines

Abstract

The Ugi reaction of 2-substituted dihydrobenzoxazepines was found to proceed with unexpectedly good diastereoselectivitiy (diastereoisomeric ratios up to 9:1), despite the large distance between the pre-existing stereogenic centre and the newly generated one. This result represents the first good 1,4 asymmetric induction in an Ugi reaction as well as the first example of diastereoselec-tive Ugi reaction of seven membered cyclic imines. It allows the diversity-oriented synthesis of various tetrahydro[F][1,4]benzox-azepines. © 2011 Banfi et al.